This article addresses the issue related to determining the minimum capacitor required for the self-excitation of an induction generator. The determination of the minimum capacitance required for the self-excitation of a self-excited induction generator has already been the subject of several previous studies. It has been shown that the minimum capacitance depends on the rotation speed and the remanent magnetism. The study carried out in this paper shows that, in addition to the rotation speed and the remanent magnetism, there is a third parameter that has an influence on the self-excitation process, which is the acceleration or, in other words, the rotation speed ramp-up. In this paper, several experimental self-excitation tests for different values of the rotation speed ramp-up are carried out, leading to new characteristics of the minimum self-excitation capacitance as a function of the rotation speed. The results obtained from simulation and experimental studies prove the efficacy of the proposed approach.

This paper aimed to evaluate the performance of a three-phase double-stage photovoltaic water pumping system. Ours is composed of several components. These include a photovoltaic array; a boost DC-DC converter with a maximum power point tracking algorithm based on the Perturb and Observe technique; a three-level neutral-point-clamped inverter, which is controlled using simplified space vector pulse width modulation; and a moto-pump group based on an induction motor and tank. The induction motor is distinguished by its rigidness, reliability and relatively low cost. However, the difficulty of controlling the induction motor is related to the fact that its mathematical model in Park configuration is nonlinear and highly coupled. The regulation of the speed, rotor flux and d-q axis currents of the Field-Oriented Control is achieved through the use of sliding-mode-control-based regulators. To evaluate the performance of the proposed control strategy, simulations were conducted using the Matlab/Simulink platform while considering varying levels of irradiation and temperature. The simulation outcomes conclusively demonstrate that the proposed system control has good performance with regard to dynamic responses, control robustness and power quality, thus affirming its efficacy. A solar water pumping system that uses photovoltaic energy has the potential to be a dependable and effective way to pump water while using sustainable energy sources.

In order to improve the reliability of electric machine drive systems, the position encoder is often replaced with an estimator, such as the extended Kalman filter. However, estimation errors can still occur, especially in machines with high pole number, commonly used in renewable energy systems. The high number of pole pairs amplifies the effect of estimation errors, leading to a substantial divergence between actual and controlled currents, potentially causing harm to the machine through the excessive heat generation or demagnetization of permanent magnets. To address this issue, an error compensation method has been proposed and tested in a control scheme for a tidal stream system based on a multipole dual-star permanent magnet synchronous generator. The method estimates the position error by determining the q-axis permanent magnet flux and correcting it through a PI regulator. Simulation results demonstrate the effectiveness of the proposed method, even with a non-null initial rotor position.

This paper presents a device designed to provide continuous electrical energy to isolated areas where connection to the power grid is expensive and unprofitable. This objective is achieved through a system that combines a wind turbine and photovoltaic panels as primary energy sources, with storage batteries and a diesel generator serving as backup sources. The main contribution of this work is characterized by the ability to ensure uninterrupted electrical power supply, even on days when renewable energy sources are less favorable. This intermittency is due to the random nature of these sources, as well as their dependency on weather and climatic conditions. Therefore, we sized each component of the hybrid system to meet the maximum required load individually under the most favorable conditions. We then modeled each energy conversion chain and developed power control laws to ensure effective set point tracking. Finally, we implemented a hierarchical energy management algorithm to define the operating modes of the hybrid system's sources, aiming to produce as much power as the load requires while prioritizing the use of renewable energy sources to minimize reliance on the storage system and the diesel generator.

This paper introduces a hybrid maximum power point tracking (MPPT) strategy for photovoltaic (PV) systems under rapidly varying irradiance conditions. The approach combines the super-twisting algorithm (STA), a second-order sliding mode control technique, with the grey wolf optimizer (GWO) in a coordinated framework where control action and parameter adaptation are jointly addressed. Unlike conventional MPPT methods that treat control and optimization separately, the proposed scheme improves transient response while limiting steady-state oscillations. The method is evaluated through MATLAB/Simulink simulations under multiple dynamic irradiance profiles, including fast-changing environmental conditions. Performance is assessed using complementary metrics, namely tracking efficiency, convergence dynamics, and root mean square error (RMSE), to provide an objective analysis. Results show that the STA-GWO strategy achieves faster convergence and improved stability compared to conventional SMC-GWO. It reaches an average tracking efficiency of 99.34%, compared to 99.19% for SMC-GWO, with reduced power fluctuations reflected by a lower RMSE. These improvements indicate a better trade-off between dynamic performance and steady-state accuracy. While this study is based on simulations, its findings require experimental validation. Future work will therefore include real-time implementation to confirm the practical applicability of the proposed approach.

Modified Topology of SEPIC Converter with High Gain Transfer Ratio for PV Applications